[deathanatos]

> Azure?

I tried a dual-stack vnet in Azure earlier this year, and eventually had to rip IPv6 out of it: flexible Postgres servers couldn't be instantiated into an IPv4-only subnet (yes, IPv4) if the vnet had IPv6 at all. (Worse, attempting to do so caused the API call to create the flexible PG instance to just time out, and it for some odd reason has a two hour timeout that suggests it's a transient internal error & you should retry. So, four hours.) I didn't really expect flexible PG to support IPv6, but that it seemed to poison the support for IPv6 for the rest of the vnet was really, really disappointing.

[jiggawatts]

It's not the only such service. NAT Gateways, VPN, Virtual WAN, and a whole host of others break if you enable IPv6 anywhere.

The reason things like Postgres break is because internally they use what is essentially a VPN Gateway to communicate with your vNet.